Automatic safety control and indicator for engines



AUTOMATIC SAFETY CONTROL AND INDICATOR FOR ENGINES Filed June 17. 1947 INVENTOR ALFRED C. KORTE ATTORNEY Patented July 15, 1952 AUTOMATIC SAFETY CONTROL AND INDICATOR FOR ENGINES Alfred C. Korte, St Louis, Mo., assignorto Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application June 17, 1947, Serial No. 755,186

4 Claims. 1

This invention relates to-improvements in control systems for internal combustion engines, and has particular reference to an improved control system operable automatically to discontinue engine operation in the event of an abnormal functional condition in the engine organization, as failure of normal oil flow in' the engin lubrication system. In this respect the invention herein disclosed is similar to my prior patent filed jointly with Kenneth Lannert, No. 2,370,249, and patented February-27, 1945. In this particular patent, as well as in the present application, the control system is for an internal combustion engine, and comprises a fuel system including an electrically driven fuel pump powered by two separate parallel electric circuits from the battery to the pump. One of the circuits includesa control means actuated by the starter motor switch,

and the othervv circuit is controlled by a, lubricant pressure operated switch. In the above patent, both said switches are placed inseries With the ordinary ignition switch for the ignition system of the engine. In' my-prior application with A. N. Szwargulski, Ser. No. 719,184, filed vDec. 30, 1946, now Patent No..2,49.7,029, dated February 7, 1950, I have shown the above system broadly with some modification of the pressure-operated switch and incorporating a signal or indicating lamp. The present application is directed to a similar combination wherein the signal or warning indicator lamp is so con'nected to the system as to perform a similar function to that performed in my .prior patent with Szwargulski, but the connection is in a novel manner, whereby to eliminate the necessity of a double-throw pressure-operated switch. With the present circuit disclosed in the instant application, a simple single-throw, single-pole pressure-operated switch is used, yet the function performed by the single or indicating lamp or device is substantially the same.

Theprincipal. object of the invention is to provide an improved automatic control system suitable in particular for use with automotive engines having a pressure lubrication system, wherein the control system is operative in response to abnormally lowpressure or pressure failure in the lubrication system, to cause, cessation of fuel delivery, with consequent stopping of the engine, and to effect a warning indication of the existence of such abnormal condition of the lubrication system.

Another object of the invention is to provide an oil pressure indicator which. does not require a.

special switch or switch point in addition to the oil pressure control provided in the fuel pump circuit as disclosed, for instance, in copending applications, Serial No. 715,558, filed December 11, 1946, now Patent No. 2,537,354, dated January 9, 1951, and Serial No. 719,184, filed December 30, 1946, now Patent No. 2,497,029, both in the names of Korte and Szwargulskil A further object is to provide a control system of the character and for the purpose indicated, which includes in th energizing circuit of the electric motor driven fuel supply pump, a warning indicator device having an electrical resistance effective whensaid device is operative, to reduce the current flow through the fuel pum motor to a value insufficient for pump motor operation, and a single pole switch operable in response to normal lubricant fiow pressures in the engine lubrication system, to by-pass the indicator device and cause the pump motor to operate the switch in response to abnormally low pressure or pressure failure in'the lubrication system, then operating to render the indicator device operative to cause cessation of pump, operation and to provide a warning indication of the abnormal.

condition of the lubrication system."

A further object is to provide a warning indie cator which will not only indicate the operation of the oil pump for the engine, but which will also indicate whether or not the fuel pump-is operating after the ignition switch'is turned to the on position.

Further objects and advantages of the present invention will appear readily'from the following description of a presently preferred embodiment thereof, as such is illustrated in the accompanying drawing.

The single figure of the drawing illustrates the be of known construction, the pump being suitably located with respect to the usual automotive vehicle supported fuel tank (not shown) for supplying fuel throughafeed line, to the engine fuel mixingdevice or carburetor (not shown) delivering fuel mixture to the engine cylinders through the engine intake manifold shown in part at II. A portion l2 of the exhaust manifold is here shown in heat supplying relation tothe socalled hot spot portion M. of the'intake manifold.

Included in the portion of the engine pressure lubrication system illustrated, is an engine. driven oil pump I5. indicated'as being of gear type,

having its intake connected by a suction conduit E6, to the engine crankcase oil pan shown in part at It. Oil under pressure delivery from the pump r 15, is conducted through pipes l9'and '20. to. the engine bearings and other operating parts (not shown) requiring lubricatioin I Engine cranking may be accomplished in the conventional manner, as by a starting or cranking motor 22 operated from the battery 260i the automotivevehicle. The starting motor circuit comprises a lead 24 extending from the negative terminal 26 of the battery, to one contact 27 of a starter switch 28, the cooperating contact 39 of l the latter being connected by lead3l to the starter'motor 22. Motor-S27. is grounded at 32 which completes the circuit to the ground connection 34 of the positive battery terminal 35. Switch 28 may be of a conventional. manual Or footoperated type, as desired.

Describing now the presently improved control system in operative association with the fuel supply. pump J and the engine pressure lubrication system, one terminal of the supply pump motor is grounded at 36-, while the other terminal thereof is. connectedby a lead or conductor 38 to a fixed contact 40 of 'asingle pole, pressure operated switch device indicated generally at 42. The movable contact member 43 of the pressure switch,

connected to a post'44, is connected to the battery by a wire 46 leading from post 44 to the vehicle ignition switch 41, and awire 48 between the ignition switch and battery terminal 2 6.

Pressure switch 42, includes casing members 50 and 5| in assembly connection at 52, and a yield-.

able or flexible diaphragm device 54 dividing the casing interior into a pressure chamber 55 and a switch chamber 56. Suitably. secured to the end wall of casing member 50, is an insulator assembly 58 supporting contact 49, post 44, and movable contact member 430i the switch,the latter being of spring character andarranged in the chamber.

56 such that in its free or untensioned condition,

the contact element 59 thereof will be. spaced from, and hence out of engagement with the fixed contact 40, as this appears in the figure; V

Carried by diaphragm 54 isaplunger 60 which extends into-switchchamber 55, and is guided in, its movement by a rigid member 62, th latter.

serving also as a diaphragm backing to limit the pressure displacementof the diaphragm. At the free end of the plunger isa-head'element or switch "tappet 63 of insulating material, engageable with switch member '43 upon pressure displacement of the diaphragm 54, to move the member to switchclosed position wherein the contacts 40 and 59 are engaged.' A suitable compression spring 64 encircling the plunger between the rigid member 62 v i i and the diaphragm, serves to bias the diaphragm and plunger device to initial position as shown in l V the drawing; wherein, the switch is open.

Pressure chamber'55 is in communication with '7 the pressure flow side of the engine lubrication.

system, as through a conduit 66 connected to the oil pressure feed pipe 20. Moreover, switch leham- I ber 56 preferably is vented in any suitable manner, as by a vent pipe 67 which in the present example, leads to connection-at 68 with the oil 4 pump suction pipe l6 (see application, Serial No. 715,558, now Patent No. 2,537,354, mentioned above).

It will be clear from the above explanation and description that a system has been described a which comprises two parallel electric circuits connecting the battery and fuel pump, one of which is controlled by the actuation of the startermotor switch and the other of which is controlled by the closing of a fluid pressure operated switch responsive to oil pressure, or the like. The present improvement over what has been described in my prior patents above-mentioned resides in the arrangementto operate the following indicator or warning device.

Arranged in shunt-circuit to the pressure switch, is an indicator lamp 16 connected by a lead H to circuit conductor 46, and by a lead 12 to conductor 38 Any other type of indicator utilizing a comparable resistance may be substituted for thelamp. The indicator lamp is located. in full view of' theautombtivevehicle operator, as upon the vehicle dashboard.

Completing the present'control circuit arrangement is an auxiliary energizing circuit for the engine fuel supply pump [6, including a. lead 14 from conductor 46 to the movable contact 15 of a relay switch '16, and alead l8 between the fixed contact T9 of the relay andithe pump motor con the engine is out of operation; Now upon closure of the ignition switch 41, indicator lamp 10 will be energized, thereby givin visual indication of the on condition of the ignition switch. The lamp, energizing circuit then obtaining. extends from battery 23, through the ignition switch, conduc tors'46 and H, lamp 110, conductors l2 and 38 to the motor of fuel pumpl (Land thence through ground to the battery. 'Ihelamp and pump motor thus are in series, but pump operation is here precluded by the current-limiting effect of the lamp. To this end, the lamp is selectedto havea filament resistance factor such that in th lighted conditionjof thelamp, the current return through 1 the pump motor to the battery will be at a value .well below the; current amperage. required for pump motor starting. In on ,examplathe pump motor whenconne'cted across the vehicle battery i 23 affording, say, a potential of 6 volts, requiresa starting current .ofapproximately 2.5 amperes and the lamp draws a current of between .25 and .5 amperes. to the resistance of the lamp will besuch as to preclude starting of the. pump, the latterthen serving. merely to complete the lamp return circuit to ground and'the battery. I i

With the ignition switch closed,'starting of the engine is effected 'by closure ofthe starting switch 28, which thereby completes the energizing circuitto the cranking motor 22; Closure of the starter switch. alsocauses switch-closure of the. relay 16, as is obvious from the circuit arrange ment, thereby establishing the heretofore described auxiliary circuit which affords direct connection of the fuel pump to the battery through Consequently, the voltage drop due 7 the closed ignition switch, and at the same time,'a direct short-circuit of the indicator lamp Hi to render the latter inoperative. The fuel pump therefore, starts and operates in the cranking period, to assurefuel supply at the engine carburetor. It may be pointed out here that while the illustrated relay-controlled, auxiliary pump operating circuit is presently preferred; an extracontact on the starting switch maybe employed, if desired. This feature is disclosed in my Patent No. 2,370,249. P

When the engine'fires and'starts under its own power, the starter switch normally is released to open position, which results in deenergization of relay 16 and consequent open-circuiting of the auxiliary pump energizing circuit. However, as this occurs, the pressure switch 42' is closed at its contacts 40 and 59 in response to pressure actuation of the diaphragm plunger assembly by the lubricant pressure then established by the engine-driven oil pump l 5 in theengin lubrication system. Closure of switch 42 completes the main energizing circuit of the fuel pump, as from the battery 23 through the ignition switch 41, conductor 46 to post 44 of the pressure switch, switch member 43, contacts 59 and 40 in engagement, conductor 38 38 to the motor of fuel pump l0, and thence to the battery through motor ground 36. Consequently, operation of the fuel pump as initiated in the cranking period, will continue throughout engine operation, providing the pressure switch remains closed. The switch 42 in establishing the pump circuit as described, shortcircuits the indicator lamp 10, so that the latter is inoperative during normal operation of the engme.

The pressure switch 42 is adapted and regulated in part through the diaphragm loading spring 64, for operation to maintain the circuit contacts thereof in closed condition, so long as the oil pressure effective on the diaphragm is within the normal range of oil pressure obtaining in the engine lubrication system consequent to engine operation between idling and maximum speeds. If for any reason during engine operation, the pressure in the lubrication system should fall below the normal minimum pressure, spring 64 will act to displace the diaphragm in the direction to retract the plunger 60 from its switchclosing position. The spring switch member 43 thereupon will move to disengage the contacts 40 and 59, thus opening the direct energizing circuit to the fuel supply pump 10, and at the same time removing the short-circuit about the indicator lamp 10. The lamp then affords a visual warning to the vehicle operator, of an abnormally low pressure of pressure failure in the engine lubrication system, and in so operating, reduces the current through the fuel supply pump motor to a value insuflicient for continued pump operation. Consequently, the fuel pump stops, and following the resultant cessation of fuel delivery to the engine, the engine will cease operation.

Thus the presently improved control system affords in the event of pressure failure in the engine lubrication system, both a visual warning indication to the vehicle operator, of such condition, and an automatic shut-down of the engine. The lamp affords a simply and conveniently available warning indication of any failure in normal operation of the engine pressure lubrication system, and coincidently when the lamp resistance is in the fuel-pump circuit it results in a reduction of current through the fuel supply pump motor such as to render the pump inoperative.

e 6 Likewise, it can be readily understood that the lamp affords a simple indicator of fuel pump operation. However, it will be appreciated that any suitable indicator device havin a resistancecharacteristic similar to that of the lamp, may be employed in the present system. For example, a bell or buzzer device maybe substituted for the lamp 70, or if desired, a lamp and bell or buzzer may be used in combination, to afford both sound and visual warning. The insertion of the usual generator and cut out in the electrical system will not adversely affect the above operation.

It is to be pointed out'here that the relatively simple yet highly effective warning indicator and fuel supply pump control system as provided by the present invention, importantly facilitates the use of a simple and inexpensive pressure switch having but a single movable contact cooperable with a single fixed contact, and wherein the pressure-closure of the switch contacts may be closely regulated through selection or the diaphragm loading spring to afford a predetermined desired biasing influence on the diaphragm. 1

Having now described the invention with re-' spect to a presently preferred embodiment thereof as illustrated by the drawing, it will be appreciated and understood that modifications of the system may be made without departing from the spirit and full intended scope of the invention as defined by th appended claims.

I claim:

1. In combination with an internal combustion engine having a pressure lubrication system, an electric motor operated fuel pump for the engine, an energizing circuit for the pump motor including a main switch, indicator means of resistance character in said circuit, said indicator means being effective upon closure of said main switch prior to engine starting for indicating circuit closure therethrough to said pump, the resistance of said means being predetermined in relation to the normal current characteristics of said energizing circuit such as to determine the current through the pump motor at a value less than that required for pump operation, a second switch con nected in parallel with said indicator means, and a pressure actuator for said second switch connected to said lubrication system for closing said second switch in res onse to th development of normal lubricant pressure in said lubricating system consequent to running operation of the engine, to form a short circuit around said indicator resistance and establish operating energization of the pump motor, said switch actuator in response to abnormal decrease of pressure in said lubricating system cutting out said short circuit and thereby causing cessation of pump operation, said indicator means then serving to indicate failure of normal pressur in said lubricating system.

2. In a power plant, an engine, a lubricating pump connected to be driven from said engine, an electrical system for said engine, including a battery, starter motor, and control switches, a fuel supply system for said engine, including an electrically driven fuel pump, two parallel electric circuits connecting said battery and said electric fuel pump, control means in on circuit to energize said fuel pump responsive to starter motor operation, and control means in the other circuit to energize said fuel pump responsive to operation of said lubricating pump, the combination with said other circuit, of means comprising a resistance circuit in shunt with said second control means and including an indicator device, said resistance circuit having resistance sufiicient to ation, andcon energize s t 7- produce 'airoltaee. ir n there l r ugh to said, fuel. ump below Qui n motor oper tin requ rement supply raid en in ine udin an electri al y d i en u l p mp wo naralleloe c ri i cui c nn in said ha tery' an said electric fuel p mp, ntrol means o e ircu to ne ize id ue pumlo respon ib e o s a ter mo or oper-v ol mean in the ther circui to oi s id hi matin pummtlie omb nation wit i said othere reuit or meanseem isi a ind cater circuit onnected p rallel r lation with .s dse end con 1 hav n an, electrica resistance sufficientto p m ans, said ndicator Circuit duce. a. vol a e drop therethrou h to said fuel mp belowtpump motor operatin r quirements. In pow plan an e i e, a lubr cat pu p connect d to e r ven. item s id en in a electrical system for said engine, including a batern, sta ter motor and control switches, a fu l p y syst m for said, en in including e1ectri- 1 pump resp nsiv ooperatio 1 a ower plant, an e ine a ubricatin Y rumoeennee d o be driven: om said e ine, an lee calsystem for said. eng ne. inc udin a b t- 1 "term, st rter m o and control switches, a uel a ly driven fuel ump, two p rall l electric cir' cuitsf connecting said battery and said electric fuel pump, control means in one circuit to ener-, gize said iuel pumpresponsive to starter motor operation, and control means in'the other circuit circuit including an electrical resistance sulficient to produce a voltage drop therethrough to saidfuel pump below pump motor operating requirements when said second control means is inopere ative. V ALFRED .C. KORTE.

, eercacsccs CIT The following referencesare of record in tho file ofthis' patent: a

UNITED STATES PATENTS Name Date Number- KQlitQ F'Gb. 27,1945 

